Why this lesson matters

Understand layouts and use it correctly in an App Router project. The App Router maps folders to route segments while page and layout files define UI and shared structure; nesting is part of the URL and rendering model.

How to reason about it

  • For Layouts, the outcome to verify is: A folder represents a route segment and page.tsx supplies that route UI.
  • In Layouts, keep this failure controlled: Adding folders without understanding whether they create URL segments can produce accidental routes and duplicated layouts.
  • Layouts practice target: Build a nested dashboard route with a shared layout and verify which UI persists while navigating between child pages.

Practical walkthrough

In the Layouts walkthrough: A folder represents a route segment and page.tsx supplies that route UI.

app/dashboard/page.tsxtsx
export default function DashboardPage() {
  return <main><h1>Dashboard</h1></main>;
}

Practice it yourself

Practice

Layouts exercise

Build a nested dashboard route with a shared layout and verify which UI persists while navigating between child pages.

  • Record the expected result before execution
  • Test one valid path and one lesson-specific failure path
  • Explain in two lines which boundary owns the decision

Summary